TMNet Streamyx, the largest internet service provider in Malaysia is now blocking outgoing port 25 to fight Email SPAM. Email spamming has recently become a very serious issue. TMNet decided to block port 25 to block all unwanted email spam which is growing day by day.
After the block of Port 25, Streamyx user will expierence problem sending out their emails using email client such as outlook and so on.
To overcome this problem, change your SMTP port.